Propellant powder



Patented Feb. 28, 1933 enonen c. HALE, or novnn, rT w annsny PROPELLANTPOWDER No Drawing.

Application filed March 1,

1932."-Seria1 No. 596,164.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928;- 3700. G. 757) The invention described herein may be manufactured and usedby or for the Govern ment for governmental purposes, without the paymentto me of any royalty thereon.

5 This invention relates to a propellant powder.

Modern propellant powders, in addition to being smokeless, are requiredto be non-hygroscopic, non-volatile and flashless. These additionalrequirements make much more difiicult the formulation of compositionswhich will also meet ballistic requirements. In the past, there havebeen two essential types of smokeless powders, the straight l5nitrocellulose powder containing a volatile solvent as colloiding agent,and double base powders in which nitrocellulose is colloided withnitroglycerine. The first type of powder composition mentioned hasappreciable Q9 volatility, is very hygroscopic and produces a largeflash at the muzzle of guns. The nitroglycerine-nitrocellulose powderson the other hand are relatively non-volatile and non-hygroscopic butare not superior to the straight nitrocellulose type in regard to theflash produced. v

One means of reducing the flash from nitrocellulose powders is toincorporate inert compounds in the powder. The decomposition of theseinert compounds consumes sufficient heat that the temperature of thegases issuing from the muzzle of the gun is reduced below the ignitiontemperature of the gases and hence no flash is produced. This is a verysatisfactory means of reducing flash but it has limitations in otherdirections in that the addition of inert compounds may re duce thepotential of the powder to such an extent that the desired ballisticscannot be obtained.

It would be highly desirable to have a compound available which wouldact as a colloiding agent for nitrocellulose and at the same timeprovide a powder which would be non-hygroscopic, non-volatile, smokelessand flashless. Certain nitroaromatic compounds have been employed in thepast in an attempt to provide such a powder but distinct weaknesses canbe cited against the use of any of such compounds employed in the pastif judged by their suitability in fulfilling all the requirements of-thepowder set forth above. Thus, all mononitro compoundsem ployed in thepast, whileimpajrting favorable properties such as non-hygroscopicity,nonvolatility and a certain tendency to reduce flash, have theobjectionable feature of being practically inert and reducing the energycontent of the powder in proportion to the amount used. Thedinitroaromatic compounds which have been used in propellant powders arecrystalline bodies and are, therefore, not colloiding agents fornitrocellulose at ordinary temperatures. In addition, although theyimpart greater potential toa c5 powder than the mononitro compound, theyhave less potential than pyrocellulose and their use with the lattermust, therefore, of necessity, reduce the potential of a powder inproportion to the percent used in a basic nitrocellulose composition.The trinitro compounds which have been used have the high potentialdesired but they are crystalline and hence are not colloiding agents fornitrocellulose at the temperatures at which powders are manufactured anddo not function as well as desired in reducing the hygroscopicity of apowder or in reducing the flash.

Thus, past experience has not yielded a single compound which, whenadded to nitrocellulose, will give a powder composition that will meetto a satisfactory degree all the requirements now demanded. I havediscovered however, a means of accomplishing this end by providingmixtures of nitro compounds which are liquids at ordinary temperature;which have a higher nitrogen content, i. e., potential than any singleliquid nitro compound; which impart the properties 9 of non-volatility,non-hygroscopicity and flashlessness to nitrocellulose powders. Thesemixtures are distinctly superior in this regard to any nitro compoundthat has previously been used with propellant powders in that theseessential requirements are met without detracting appreciably from theenergy content orrpotential of the nitrocellulose. They are, in effect,double base powders in which the objectionable features ofnitroglycerine have been eliminated by substituting a liquid mixture ofnitro compounds for nitroglycerine.

Examples of compositions which have been prepared and demonstrated byfiring tests and chemical tests to meet the requirements mentioned aboveare cited as follows:

7 Per cent a. Nitrocellulose 85 Trinitrotoluene 5 Mononitrobenzene 10 b.Nitrocellulose 80 Trinitrotoluene l5 Mononitrobenzene 5 'As ageneralipropos-ition it may be stated that the TNT may be present inamounts from .5 to 15% and the mononitrobenzene in amounts from 2 to 10The advantage of .mononitrobenzene over the mo'nonitro compounds oftoluene, xylene and naphthalene resides in the fact that it contains alower percentage of carbon and a higher percentage of oxygen. 'Thebenzene moleculecontains only six carbon atoms while toluene containsseven, Xylene contains eight and naphthalene contains ten.

. I olaimz; V

A propellant powder consisting of nitrocellulose, trinitrotoluene 5 to15 per cent and 'mononitrobenzene 2 to 10 per cent.

GEORGE C. HALE.

